1. Field of the Invention
The present invention relates to systems, methods and apparatus for securing tissue to bone. More particularly, the invention relates to apparatus and methods for facilitating the attachment of tissue to bone using a bone anchoring system.
2. Description of the Related Art
Many attempts have been made to provide devices that allow the arthroscopic securing of torn tissue to a human bone. For example, numerous devices have been designed to allow a torn rotator cuff to be secured to a humeral head of the shoulder.
Typically, in a first step, a hole is drilled into the bone under arthroscopic visualization. A length of a suture length is threaded through a portion of a tissue, and then coupled to a bone anchor configured. One or more sutures may be manipulated outside of the arthroscopic site.
Once the suture is coupled between the tissue and the bone anchor, the bone anchor may be inserted into the hole. The bone anchor may be configured to lock itself within the hole in the bone upon deployment therein. Several means for securing the bone anchor within the hole of a bone are known in the art.
Once the bone anchor is secured within the hole in the bone, one or both ends of the suture may be tensioned to approximate the positioning of the tissue with respect to the bone. Once the tissue is positioned as desired, the suture may be locked in place to maintain the tension in the suture. The free end or ends of the suture may be clipped under arthroscopic visualization to complete the procedure.
An example of a previously known method and apparatus for attaching tissue to bone is described in U.S. Pat. No. 6,585,730 to Foerster, which is incorporated by reference herein. Foerster describes devices and methods for securing sutures to a bone anchor without the requirement of knot tying. In Foerster, suture legs, after having been placed into soft tissues to be anchored to bone, are threaded through the anchor and then through a floating wedge block located at the distal end of the anchor. The wedge block is configured such that it has a hollow lumen through the center, and a conically tapered outer surface. The sutures are passed back around the outside of the wedge block such that they rest on the conical surface. They are then re-threaded in the opposite direction back through the anchor, exiting the anchor at the proximal end thereof. The anchor is then inserted into the bone, and secured. When tension is placed on the legs of the suture passing back out of the anchor, the suture is drawn through the hollow center lumen, around the distal end of the wedge block, and back out of the anchor. This tension tends to cause the wedge block to force its way back up into the anchor body, and a means to prevent this may be employed. Such means may include any structure that selectively holds the wedge block separate from the anchor body.
At this juncture, by pulling on the suture legs, any slack in the sutures is removed, and the soft tissues are drawn toward the anchor. When the soft tissues are in the desired orientation, relative to the bone to which they are to be attached, the structure holding the wedge block is removed, and the back tension on the sutures pulls the wedge block into the matching taper in the anchor body, maintaining the compressive force on the suture legs.
Another previously known knotless suture anchor is described in U.S. Pat. No. 6,692,516 to West et al. (“West”), which is incorporated by reference herein. West describes a knotless suture anchor and method for knotlessly securing. The suture anchor has a deformable portion for engaging with a wall of a borehole in a first tissue member, a shaft for providing a force to the deformable portion to deform the deformable portion to cause the deformable portion to engage the wall of the borehole, a suture retaining portion in at least one of the deformable portion and the shaft for retaining two suture portions in the retaining portion with a loop formed between the two suture portions. The loop is adapted to traverse a second tissue member to be attached to the first tissue member. Application of the force to deform the deformable portion causes engagement of the deformable portion with the borehole to secure the suture anchor to the first tissue and clamping of at least one of the two suture portions in the suture retaining portion thereby to secure the suture forming the loop in the suture retaining portion and secure the second tissue to the suture anchor.
Systems, apparatus and methods are desired for securing tissue to bone that allow direct tactile feedback of the tension in the suture between the tissue and bone. During securing tissue to bone, it is desired to be able to adjust positioning of the tissue with respect to the bone. In securing the tissue to bone, the suture may be locked in place without tying a knot.